In recent years, the needs for hybrid electric vehicles, electric vehicles, and others have been increased. Accordingly, motors have been studied to be used for the driving power of vehicles. However, such motors to be mounted in the vehicles are demanded for high power and downsizing. Particularly, hybrid electric vehicles are strictly demanded for size reduction in view of the placement of a motor in an engine room.
Therefore, various studies have been made to achieve downsizing and high power of motors.
Patent Literature 1 discloses a technique related to a conductor part for stator frame in a multi-phase power generator.
A stator core includes outer slots. A flat rectangular conductor provides a plane of an in-slot conductor portion to be inserted in each slot. The flat rectangular conductor is shaped into an almost U-like form when seen in plan view perpendicularly to the plane and a sinuous form when seen in front view along the plane. Such flat rectangular conductor is set in the stator core. Accordingly, a coil end of the stator can be shortened, thereby improving the space factor.
Patent Literature 2 discloses a technique related to a crank-shaped consecutively wound coil, a distributed winding stator, and a method of forming them.
After a flat rectangular conductor is wound in hexagon shape, a crank-shaped portion serving as a coil end is formed by a die. Such flat rectangular conductor is placed in a stator core to eliminate interference between coils in the coil end, thus contributing to an increase in the space factor of the stator and a reduction in size.
Patent Literature 3 discloses a technique related to a rotary electric machine and a manufacturing method thereof.
When a coil assembly wound from an inner circumferential side to an outer circumferential side is to be placed in slots of a stator core, the coil assembly is inserted from the coil outer circumferential side in an outer layer side of one slot and from the coil inner circumferential side in an inner layer side of the other slot. Accordingly, the rotary electric machine including distributed winding coils can be manufactured in a simplified work and also can have an improved space factor of the slots.
Patent Literature 4 discloses a technique related to a stator of a rotary electric machine, and the rotary electric machine.
A flat rectangular conductor is wound in wave form to form a wound coil having a plurality of phases. Split teeth are inserted from outside and fixed in grooves in an outer annular portion of a stator core. Thus, the stator core can be manufactured with high precision.